Television receiver



H- E. KALLMANN TELEVISION RECEIVER May 2 1950 3 Sheets-Sheet 1 Filed Oct. 25, 1946 INVENTOR. b

y 1950 H. E. KALLMANN 2,505,862

TELEVISION RECEIVER Filed Oct. 25, 1946 3 Sheets-Sheet 2 A INVENTOR.

May 2, 1950 KALLMANN 2,595,862

TELEVISION RECEIVER 3 Sheets-Sheet 5 Filed Oct. 25, 1946 INVENTOR. H- E Kqfl BY Patented May 2 1950 tum-r t ain STATES PATENT torn-CE TEL V S RECE ER I IeinaE; Kaiimann, NewYork, N. Y.

,. Application October 25, 1946, Serial No.;7 05,717

(Cl. ZED--40) It is also an objectof my ip'resent invention to providela television receiver witna local oscillatorfstag'e the frequency oflwhich" is isol, stabilized thatlno tuning correetion' is'needed during operanonor theirec'eiyer.

Finally, it is also ian object of my present inyent'ion to provide for receivers'otthe above. type a push, button;tuningassembly which is of small dimensions fsuitable Qfor the newly ,developed m iature amplifier tubes and gconstructed so as to reduce wiring reactances at the high V freql fes nv l e Withv the [above objects View, my present ntion comprises. m television. receiverv the k'zon i'iiliation of an electricaltelevision receiver eircuit, at least/one stationary contact member included in this .receivergcircuit a rnovable push button switch Qmernber, an electrical tun n ele-- ment forming part 1. of the 7 receiver circuit and combined with, 1;. ,g. carried by; this movable .push huttonswitch meinber,1at least one movable contact member combinedwith, ,eQgl mounted on the above mentioned movable 'push button switch memberper'manently connected with the electrical element combined withge'. g. carriedby this switch member, f and ,guiding means constructed and arranged so as to be adapted to guide the switch member between .t inoperative position 7 in which the movable .con ta ct member combined f ith, e. g. mounted on: the switch member; is ont of? contact with the" stationary contact member mentionedaboveand operative position in which hi ml l C ntac m mbe s-mo e nto con tes wit h s tt pnar l sonn m m i'l e se daiwa tharsf r d embod m nt-p Pre en inventiQn th -mcvab1e conta :mem:

her or members are mounted directly on the electrical tuning element combined with, e. g.

carried 7 by the switch member. Usually, such tuning elements include a tuning coil and in this event the movable contact-members are connected directly to the endsof the coil.

I have found itadvisable to provide two movable contact members for each tuning element combineclwith, e. g. carriedby the switch member and two corresponding stationary. contact members adapted f t0 engage these movable contact members when the switch member, is in operative position.

a television-receiverpf,the particular type proposed by me comprises usually three stage namely a radio frequency amplifier stage, a radio frequency mixer stageiand alocal oscillator stage. Each of the first twostagesl mentioned includes a tuning coil, while the local oscillator stage includesa line section of .yvellknown type. I have found it advisable .to use for television receiversof the t pe proposed by me and described below in detail line sections of the typedisclosed in my co-pending U.,.S., patent application Serial No.

679,920, filed vJ uiegil, 1946, and entitled improvements in Line sections.

The above mentioned .three tuning elements, namely, the two tuning coils and the line section, are combined, in accordance with I my present 2 invention,--,withthe movable switch member, e. g. mounted onand carried by the same. Each of these elements, is provided'with a pair of contact members which move togetherwith the movable switch member when the switch is operated. Furthermore in a receiver of this type, I provide three pairs of stationary contact members corresponding to the three pairs of movable contact members mentioned above and arrange these stationary contact members so as to engage the corresponding movablelcontact members when he movable switch member is in operative position.

By providing a switch arrangement of the above type it is possible to obtainsubstantial advantages compared with arrangements of conventional type: first, it is possible to reduce and keep the length-of the connecting wires to a minimum; and second, thenumber of contact members in each pathis halved compared with the usual type of push-button switches connecting fixed tuning elements with other fixed cir-- cuit elements-by sliding twinlcontacts.

Thenovel features-which I consider as characteristicrformy invention are set forth in particular in, the; appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a top view of a push button tuning arrangement for a television receiver according to my present invention;

Fig. 2 is a cross section through the push button tuning arrangement shown in Fig. 1 along line 2-2 of Fig. 1, in operative position;

Fig. 3 is a cross section through the push button tuning arrangement shown in Fig. 1 along line 3-3 of Fig. 1, in inoperative position; and

Fig. 4 is a circuit diagram of a television circuit embodying a push button tuning arrangement according to my present invention.

As shown in Figs. 1 and 2, my new push button tuning arrangement includes a rigid frame I6 mounted on the chassis of a television receiver, a plurality of push button rods II passing through corresponding openings I2 and M in the cross bars I3 and 15, respectively, guided by the same so that the'rods are adapted to slide in direction of the arrow I5 whenever pressure is exerted against one of the buttons I? provided at the front ends of rods I I.

Springs it are provided at the rear ends of the push button rods II tending to force the same outward in direction of arrow I9. These springs I6 abut at their rear ends against the cross bar I5 and at their front ends against the faces 26 formed by the cut-outs 2| in the push button rods II. v

In order to hold any one of the push button rods in pushed-in operative position shown in Fig. 2-, a latch bar 22 is arranged as shown. This latch bar 22 is slidable in axial direction and provided with a plurality of hook-shaped projections 23 adapted to engage in well known manner the apertures 24 and 25 provided in the push button rods ll.

As operation of such push button arrangements is well known to everybody skilled in this art, I will not describe it in detail. It should only be noted that an arrangement of this type operates in such a manner that if one of the push button rods is in pushed-in operative position and it is desired to move it outwards. into inoperative position, this can be attained by moving any of the other push button rods inward in direction of arrow 56. This will result in sliding of the latch bar 22 in direction of arrow 26, disengaging the inward moved push button rod and permitting the corresponding spring to move this rod in direction of arrow I9 into inoperative position.

In accordance with my present invention, I provide on top of each of the push button rods I l a supporting platform 21' as clearly shown in Figs. 1 to 3. This platform might consist of one piece. However, in certain cases it is advisable to make the platform 21 of several pieces, e. g. by providing in the platform a cut-out and mounting on the platform an insulating plate 28 covering this cut-out, as shown.

The supporting platform 2'! carries the three tuning elements 29, 36 and 3i, which will be described farther below in detail. It should only be mentioned that the tuning elements 29 and 30 include tuning coils 33 and 32, respectively, of usual design, while the tuning element 3I consists in the embodiment shown of a quarter wave line section including a coil-shaped metallic coating 34 on an insulating tube 35.

The above described three tuning elements are mounted by means of screws 36, 3'! and 38 on platform 21 and insulating plate 28, respectively. Nuts 39, 40 and 4| engaging the screws 36, 31 and 38 serve to hold the tuning element in proper position.

Each of the tuning elements 29, 36 and 3| is provided with two contact members: the tuning element 29 is equipped with the contact members 42 and 43 firmly secured to the ends of the tuning coil 43; the tuning element 36 is equipped with the contact members 44 and 45 firmly secured to the ends of the tuning coil 32; and the line section 3I is provided with the contact plate 46 provided at the end of the coil-shaped metal coating 34 on the outer surface of the insulating tube 35 and the contact spring 41 connected to the end of the straight strip-shaped coating 48 on the inner surface of tube 35.

In addition to the movable contact members described in the preceding paragraph, I provide three pairs of stationary contact members cooperating with the movable contact members. All these stationary contact members are firmly mounted on frame I0 so that they contact the corresponding movable contact members when one of the push button rods I l is moved into operative position.

Each of the stationary contact members consists of a metallic conductor provided with a plurality of contacts corresponding to the movable contact members:

Thus, I provide two conductors 49 and 50 mounted on the insulating strip-shaped support 5I and electrically connected with the contact springs 52 and 53, respectively. The insulating support 5| is mounted by means of brackets 54 on frame ID, as clearly shown in Figs. 1 and 2. The contact springs 52 and 53 are arranged so as to be adapted to engage the movable contact members 42 and 43 respectively when the same are in operative position as shown in Fig. 2.

Similarly, I provide the conductors 55 and 56 mounted on .the insulating plate 51 and electrically connected with the contact springs 58 and 59, respectively, These contact springs cooperate with the movable .contact members 44 and 45, respectively, as shown in Fig. 2. The insulating plate ,5! is supportedby the brackets 66 so that the contact springs 58 and 59 are in proper position engaging the contact members 44 and 45 when the push button rod I I is pushed inward into the position shown'in Fig. 2.

Finally, the conductors 6| and 62 are mounted on the insulating plate 63 and electrically connected with the contact springs 64 and 65, respectively. These contact springs are adapted to engage the contact plates 46 and 41, respectively, when the line section 35 is in operative position shown in Fig. 2. The insulating plate 63 together with the conductors BI and 62 and the contact springs 64 and 65 are mounted on frame I6 by means of the brackets 66 as shown.

My new above described television switch arrangement is operated as follows:

In order to switch from one television channel to another, it is only necessary topress against that push button rod I I which carries those tuning elements which correspond to the desired channel. By doing so, all three tuning elements are moved inward and connected by the movable contact members forming part of the same with the stationary contact springs included in the "ground I l.

. caresses :television circuit. As already:mentionedabove,by

an arrangement of. thistype it is possible to keep sethelengthofthe connecting wires to a minimum and togreatly reduce the number of contacts in each path, thereby-substantially reducing the wir- -;ing,.-r'eactances due to long' wires and numerous contact members.

w Although already mentioned-above, I-wish to :stressthat-each of the pushbuttonrods ll carries differently tuned tuningelements each adjusted to a specifictelevisionchannel.

A switcharrangement'of the above. type might .be .used in television receivers of various types. c However, I have-found that a switch arrangement :of the type proposed byme is of special advantage itused in combination with a television circuit of thetype shown inFig. 4.

. Thistelevision-circuit includes three tubes of whichthe. first,- namely, -tube 61 performs the radio frequency amplification, the second, namely,

tubeafi8, mixes the outputot tube 6.1 with the oscillations generated by the local oscillator, and the 'third, namely, tube 69, activates the local oscil- -lator circuit.

The television signals are fed from a low impedance feeder cable to the terminal is and The input tuning circuit of the receiver consists of the tubeinput capacity shown as a separate condenser 12, a matching con- ..denser 13 and the tuning coil 33. This tuning coil 33shown.a1so inaFigs. 2-and 3-is connected by means of the movable contact members 42 and 43 and the stationary contact members 52 -and153 to the rest of-the-circuit.

-"I'hetelevision signals stepped up by the above .described input tuning circuit are fed to'the signal gridof tube 61. The anode ofthis tube .-is.1supplied. with positivepotential via the resistance 14; the screen grid of the tube is suppliedwith. positive potential via the resistance J5 and is decoupled by condenser 16.

-'The coupling circuit betweenthe radio frequency amplifier stage described above and the mixer tubev 68.is provided by the circuit made ,-up of the input capacity and/or external capac .ity'll and the tuningcoil 32. This tuning coil :32 is, as,.clearly shown in Fig. 2, connected with the circuit by means ofithe movable contact .members 44 and .45 and the corresponding stationary contact members 58 and 59, respectively.

The coupling circuit is coupled to the radio frequency .amplifierstage by the condenser 18 i andto the mixerby condenser I9. The grid-leak --resistor 8!) serves to establish adequate bias by rectification of local oscillator power.

wflhe local oscillator tubeBS isied-at-its-anode :sw-ith v:high voltage via theresistance M and choke 82 and-suitablyibiased.at its grid via resistance 83.

.Thistube 169 is tuned by the line.section135 iwhich isconnected by means of the movable con- :tacts. and .4! and the corresponding stationary contact springs 64 and 65, respectively, on the one handto. the anode of tube 69-and on the :.other hand to the grid of this tube via con- 1denser ;84.

.The output of the above described local .oscilelator tube 59 .is coupled to the grid of themixer tube-6B via condenser 85, and the output of this mixer tube is taken oir its anode viacondenser :85.

1.-All three tubes included in the circuit are .suppliedwith high voltage from .source 8Land with eheater voltage from source 88.

@Thetuning ,coilss32 land-:33 andthe-line sectypes described above.

tion 35are-mountedon the push button rod] 1 as described above and slidable: into 3 contact. with the; corresponding stationary contact members by pressing against the knobd'l.

It isevident that, as shown. in Figs. 1. to 3,4; pluralityv of .groups of tuning elements 32, 433 and 35 are provided; each ofthese groups of tuning elements .is carried byv one of the push button rods l I and can be included into the television circuit as-describedabove so as. to adapt the same'to difierent television channels.

It will beunderstood that each of the elements described above; or two or more together,- may also find a useful-application in other types :of

electrical signal receivers differing from .the

' While I have illustrated and described :the invention as embodied in television receivers, I

do not intend to belimited to the details shown, since ing and range oflequivalence of the following.

claims.

What I claimas new and desire to secure. by

- Letters Patent is:

1. In a televisionreceiver an electrical television receivercircuit; a plurality of stationary contact member arrangements included. in. said electrical television receiver circuit; a movable push button switch; a plurality of electrical tuning elements forming part of .said electrical television receiver circuit and adapted to be moved by said movablepush button switch member; .a

plurality of movable contact member arrangements also adapted to .be moved by said movable push button switch member, each of said movable contact member arrangements permanently connected with atermination of one of said electrical tuning elements; and guiding means for said movable push. button switch member constructed and arranged so as .to be adapted toguide said movable push button switch member during its movement between inoperative position with said movable contact member arrangementsout of contact with the corresponding stationary contact member arrangements and operative position with said movable contact member arrangements moved into contact with the corresponding stationary contact member arrangements.

2. In a televisionreceiver an electrical television receiver circuit; aplurality of pairs of stationary contact members included in saidelectrical television receiver circuit; a movable push button switch member; a supporting shelf-like member constructed and-arranged so as tobe adapted to be moved by said movable push button switch member; a plurality of electrical tuning elements forming. part of said electrical television receiver circuit and mounted-on said supporting shelf-like member; a plurality of pairs of movable contact members, each of saidpairsof movable contact membersmounted on and permanently connected with a -termination ofone of said electrical tuning elements; .and guiding veasoegeera means for said movable ush'button switch memberconstructed and arranged so as to be adapted to guide during its movement said movable push button switch member between inoperative position with said pairs of movable contact members .out of contact with the corresponding pairs of .member included in said electrical television receiver circuit; a first tuning member forming part of said radio frequency amplifier stage and mounted on said movable switch member; a second tuning member forming part of said mixer stage and mounted on said movable switch member; a line section member forming part of said local oscillator circuit and mounted on said movable switch member; first movable contact means mounted on said first tuning member electrically connected with a termination of the same and carried together with said first tuning member by said movable switch member; second movable contact means mounted on said second tuning member electrically connected with a termination of the same and carried together with said second tuning member by said movable switch member; third movable contact means mounted on said line section member electrically connected with a termination of the same and carried together with said line section member by said movable switch member; first stationary contact means arranged and constructed so as to be adapted to cooperate with and engage said first movable contact means; second stationary contact means arranged and constructed so as to be adapted to cooperate with and engage said second movable contact means; third stationary contact means arranged and constructed so as to be adapted to cooperate with and engage said third movable contact means; and guiding means for said movable switch member constructed and arranged so as to be adapted to guide during its s movement said movable switch member between inoperative position with said movable contact means out of contact with the corresponding stationary contact means and operative position with said movable contact means moved into contact with the corresponding stationary contact means.

. 4. In a television receiver an electrical television receiver circuit; a radio frequency amplifier stage forming part of said electrical television receiver circuit; a mixer stage forming part of said electrical television receiver circuit; a local oscillator stage forming part of said electrical television receiver circuit; a movable switch member included in said electrical television receiver circuit; a first tuning member forming part of said radio frequency amplifier stage and mounted on said movable switch member; a second tuning member forming part of said mixer stage and mounted on said movable switch men ber; a line section member forming part of said local oscillator circuit and mounted on said movable switch member; a first movable pair of contact members mounted on said first tuning member electrically connected with a termination of the same and carried togetherwith said first tuning member by said movable switch member; a second movable pair of contact members mounted on said second tuning member electrically connected with a termination of the same and carried together with said second tuning member by said movable switch member; a third movable pair of contact members mounted on said line section member electrically connected with a termination of the same and carried together with said line section member by said movable switch member; a first stationary pair of contact members arranged and constructed so as to be adapted to cooperate with and engage said first pair of movable contact members; a second stationary pair of contact members are ranged and constructed so as to be adapted to cooperate with and engage said second movable pair of contact members; a third stationary pair of contact members arranged and constructed so as to be adapted to cooperate with and engage said third movable pair of contact members; and guiding means for said movable switch member constructed and arranged so as to be adapted to guide during its movement said movable switch member between inoperative position with said movable pair of contact members out of contact with the corresponding stationary pair of contact members and operative position with said movable pair of contact members moved into contact with the corresponding stationary pair of contact members.

5. In a television receiver an electrical television receiver circuit; a radio frequency amplifier stage forming part of said electrical television receiver circuit; a mixer stage forming part of said electrical television receiver circuit; a local oscillator stage forming part of said electrical television receiver circuit; a movable switch member included in said electrical television receiver circuit; a first tuning member comprising a metallic coil forming part of said radio frequency amplifier stage and movably carried :by said movable switch member; a second tuning member comprising a metallic coil forming part of said mixer stage and movably carried by said movable switch member; a line section member comprising a metallic coil forming part of said local oscillator circuit and movably carried by said movable switch member; a first movable pair of contact members mounted on said first tuning member electrically connected to the ends of said metallic coil forming part of the same and carried together with said first tuning member of said movable switch member; a second movable pair of contact members mounted on said second tuning member electrically connected to the ends of said metallic coil forming part of the same and carried together with said second tuning member by said movable switch member; a third movable pair of contact members mounted on said line section member electrically connected to the ends of said metallic coil forming part of the same and carried together with said line'section membe by said movable switch member; a first stationary pair of contact members arranged and constructed so as to be adapted to cooperatewith and engage said first pair of movable contact members; a second stationary pair of contact members arranged and constructed so as to be adapted to cooperate with and engage said second movable pair of contact members; a third stationary pair of contact members arranged and constructed so as to be adapted to cooperate with and engage said third movable pair of contact members and. guiding-imeensaror saidemovable.

switch member-constructed and arranged so as to be adapted to guide-said movable-switch member between inoperativeposition witha said movable pair of contact members outtofccontact'with the corresponding stationarypair 'of'. contact members and operative position; with said movable mirror-contact members-moved into-contact with the-corresponding stationary ypair' ofcontact members.

6. In a television :receiver an electrical; tele vision receiver circuit; a plurality: of; pairsr-of stationary contact. members.- -includede.in said-elec trical television receiver-circuit; a plurality of movable switch members; a plurality of groups? otelectrical tuningelem'ents formingpart of said electrical televisionrreceiver: circuit; each of. said groups "-of' electrical tuning-c elements combined with one of 7 said movable aswitchtm'embers mov-- abIetogether-Withthe samepa pluralityof groups of pairs of movable-contact memberacach of said groups of pairs-of movable-contact members combined with one ofvsaid movable:switchtmembers andach of said pairs of movable contact mema bers'of each of:saidgroups ofipah s of movable contact members permanently :connected with a termination of one of said-electrical tuning: elements :forming part of.=said groups ofbtuning' elements combinedwith saidmovable-switch mem bers'; and a plurality of guiding meansior said movable push-button switch: members; each of said'guiding means:=constructed'r'and arrangedso as to be adapted to guideonebf said movable switch 4 members between inoperative position with the groupof:pairs-of:movable contactvmemberscombined with-isaidswitchimember out of contact with thecorresponding pairssofirstationarycontact members and-operative position with said group of pairs "of movable acontactzmembers moved into contact with :the corresponding pairs of stationary contact members; i

7;"In a television receiver anwelectrical J teleI-:- vision'receivercircuit; ac-radio frequency ampli-:

fierrstage forming-part ofsaidelectricattelevision receiver circuit; a mixer-stage formingpartor said electrical television i'receivercircuit; a-local oscillator stage formingt-part of saidcelectrical television receiver: circuit; a plurality ofmovable switch members included inivsaid electri'cahtelevision receiver circuit; a pluralitygof differently tuned first tuning members forming part Of said radio frequency amplifierrstage; each of' saiddif ferently tuned firsttuning members movably carried "by one :of'said movable :switch members; a plurality "of" differently: 'tuned' se'cond tuning members 'forming partjof said-mixerstage; each offsaid differently tuned=-second tuning= members movablyxcarried' by!- one of:said movable switch members"; a pluralityofldifferently adjusted line section members forming partbf said local oscillator stage; each of said; difi'erently adjusted line section members movably carried-by one of' said movable switch? members; a- ':-plurality of- 1 first movable contact meansgeachof said first: movable contact means mounted on 'onei'or isaid.differently tuned first tuning members electricallyconnected with a "termination:ofwthexsame and CaITiBdtQ-s gether with said fir'st tuningfimemberi byith'e mov able switch member carrying saidi first; tuningmember; a "pluralityofsecond movable contact means; each of -sa-id i-second :movable contact means mounted onv-onerofsaidv differently tuned-- second; tuning: members =aelectri'cally connected withia terminaticncofi ther-samerandwcarried toe getherawith saidisecond; stuningmnembercby-1 the:-

and engage, each of said first movable contact means; second stationary contact means ar-, ranged and constructed so as to be adapted .to. cooperatewith an .engage'each of said second movable contact means; third stationary contact means arranged and constructed so as to be adapted to cooperate with and engage each of; said third movable contact means; and a pluralitygofguiding means for said movable'switch members-cachet said guiding means constructed and arranged so-as to be adapted tov guide one-of.- sa-id movable switch members between inopera-= tive position with the-movable contact means carried by-said movableswitch member out-or contact With the corresponding stationary contact means and operative position with the mov able-contact means carried by said i movable. switch member moved into contact with the-correspondingstationary contact means.

8. -In a television receiver an electrical television receiver circuit; a radio frequency am'pli fier: stage forming part of said'electrical tele-;

vision receiver circuit; a mixer stage formingpart of saidelectrical televisionreceiver circuit;- a localoscillator stage formingpart of said electrical television receiver circuit; a plurality ofmovable-switch members included in said electricaltelevision receiver circuit; a, plurality of dif,

ferently tuned first tuning members formingpartr of saidradio frequency amplified stage, each i of.

said diffierently tuned first tuning members movably-carried by one of said movable switch mem-i bers;ap1urality of differently tuned second tun-.1 ing members forming part of said mixer stage each of said differently tuned second tuning mem berszmovablycarried by one of said movable.

switchrmembers; a plurality of difierently adjustedline section members forming part of saidlocal oscillatorstage, each of said differently adejustedline section members movably carried byone of said: movable switch members; aplurality:

of first movable pairs of contact members, eachof. said first movable pairs of contact members mounted on ionehofflsaid differently tuned first tuning members electrically connected with a termination of the same and carried togetherwithzsaid first tuning member by the movable switch member carrying said first tuning memher; a plurality of second movable pairs of contact members, each of said second movable pairs of contact-members mounted on one ofsaid differently tuned second tuning members electrically-connected.-witha termination of the same and carried together with said second tuning-- member by-the movable switch member carrying.v

said-'secondtuning member; a plurality of third movable pairs of. contact members, eacliof -said third'movable pairs'of contact members mounted on oneof. said differently adjusted line section members electrically connected with a termina-. ticn of the same and carried together with saidline section'member by the movable switch meme l bar-carrying 'saidline sectionmembers; a first stationary'pairof contact members arranged and: constructed so as to be adapted to cooperate with and engage each of said first movable pairs of contact members; a second stationary pair of contact members arranged and constructed so as to-be adapted to cooperate with and engage each of said second movable pairs of contact members; a third stationary pair of contact members arranged and constructed so as to be adapted to cooperate with and engage each of said third movable pairs of contact members; and a plu rality of guiding means for said movable switch members, each of said guiding means constructed and arranged so as to be adapted to guide one of said movable switch members between inoperative position with the movable pairs of contact members carried by said movable switch member out of contact with the corresponding stationary pairs of contact members carried by said movable switch member into contact with the corresponding stationary pair of contact members.

9. In a television receiver an electrical television receiver circuit; a radio frequency amplifier stage forming part of said electrical television receiver circuit; a mixer stage forming part of said electrical television receiver circuit; a local oscillator stage forming part of said electrical television receiver circuit; a plurality of movable switch members included in said electrical television receiver circuit; a plurality of differently tuned first tuning members forming part of said radio frequency amplifier stage; each of said differently tuned first tuning members comprising a metallic coil movably carried by one of said movable switch members; a plurality of differently tuned second tuning members forming part of said mixer stage, each of said differently tuned second tuning members comprising a metallic coil movably carried by one of said movable switch members; a plurality of differently adjusted line section members forming part of said local oscillator stage, each of said differently i adjusted line section members comprising a metallic coil movably carried by one of said movable switch members; a plurality of first movable pairs of contact members, each of said first movable pairs of contact members mounted on one of said differently tuned first tuning members electrically connected to the ends of the metallic coil forming part of the same and carried together with said first tuning member by the movable switch member carrying said first tuning member; a plurality of second movable pairs of con-- tact members, each of said second movable pairs of contact members mounted on one of said differently tuned second tuning members electrically connected with the ends of the metallic coil forming part of the same and carried together with said second tuning member by the movable switch member carrying said second tuning member; a plurality of third movable pairs of contact members, each of said third movable pairs of contact members mounted on one of said differently adiusted line section members electrically connected with the ends of the metallic coil forming part of the same and carried together with said line section member by the movable switch member c/arrying said line section members; a first stationary pair of contact members arranged and constructed so as to be adapted to cooperate with and engage each of said first movable pairs of contact members; a second stationary pair of contact members arranged and constructed so as to be adapted to cooperate with and engage each of said second movable pairs of contact members; a third stationary pair of contact members arranged and f5 one of said electrical tuning elements electrically- 12 constructed so as to be adapted to cooperate with and engage each of said third movable pairs of contact members; and a plurality of guiding means for said movable switch members, each of said guiding means constructed and arranged so as to be adapted to'guide one of said movable switch members between inoperative position with the movable pairs of contact members carried by said movable switch member out of contact with the corresponding stationary pairs of contact members and operative position with the movable pairs of contact members carried by said movable switch member into contact with the corresponding stationary pair of contact mem-' bers.

10. A push button switch member comprising a stationary frame; a push button rod slidably mounted in said stationary frame; a supportin platform combined with said push button rod so as to be slidable together with the same; stationary contact means mounted on said stationary frame; an electrical tuning element mounted on said supporting platform slidably together with the same and said push button rod; slidable contact means mounted on said electrical tuning element electrically connected with at least one termination of the same; and guiding means forming part of said stationary frame and arranged and constructed so as to be adapted to guide said push button rod together with said supporting platform, said electrical tuning ele-' ment and said slidable contact means forming part of the -same between inoperative position with said slidable contact means out of contact with said stationary contact means and operative position with said'slidable contact means moved into contact with said stationary contact means.

11. A push button switch member comprising a stationary frame; a push button rod slidably mounted in said stationary frame; a supporting platform constructed and arranged so as to be slidable together with said push button rod; a pair of stationary contact members mounted on said stationary frame; an electrical tuning element including a metallic coil mounted on said supporting platform slidably together with the same and said push button rod; a pair of slidable contact members mounted on said electrical tuning element electrically connected with the ends of said metallic coil forming part of said electrical tuning element; and guiding means forming part of said stationary frame and arranged and constructed so as to be adapted to guide said push button rod together with said supporting platform, said electrical tuning element and said pair of slidable contact members electrically connected with the ends of said metallic coil forming part of said electrical tuning element between inoperative position with said pair of slidable contact members out of contact with said pair of stationary contact members and operative position with said pair of slidable contact members moved into contact with said pair of stationary contact members.

12. A push button switch member comprising a stationary frame; a push button rod slidably mounted in said stationary frame; a supporting platform moved by said push button rod; a plurality of contact means mounted on said stationary frame; a plurality of electrical tuning elements mounted on'said supporting platform slidably together with the same and said push button rod; a plurality of slidable contact means, each of said slidable contact means mounted on connected with a termination of the same; and guiding means forming part of said stationary frame and arranged and constructed so as to be adapted to guide said push button rod together with said supporting platform, said electrical tuning elements and said plurality of slidable contact means electrically connected with terminations of said electrical tuning elements between inoperative position with said plurality of slidable contact means out of contact with the corresponding stationary contact means and operative position with said plurality of slidable contact means moved into contact with the corresponding stationary contact means.

13. A push button switch member comprising a stationary frame; a push button rod slidably mounted in said stationary frame; .a supporting platform carried by said push button rod; a plurality of pairs of contact members mounted on said stationary frame; a plurality of electrical tuning elements each including a metallic coil mounted on said supporting platform slidably together with the same and said push button rod; a plurality of pairs of slidable contact members, each of said pairs of slidable contact members mounted on one of said electrical tuning elements electrically connected to the ends of the metallic 14 coil forming part of said electrical tuning elements; and guiding means forming part of said stationary frame and arranged and constructed so as to be adapted to guide said push button rod together with said supporting platform, said electrical tuning elements and said plurality of pairs of slidable contact members between inoperative position with said plurality of pairs of slidable contact members out of contact with the corresponding pairs of stationary contact members and operative position with said plurality of pairs of slidable contact members moved into contact with the corresponding pairs of stationary contact members.

HEINZ E. KALLMANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,697,196 Macgahan Jan. 1, 1929 2,154,778 Schnell Apr. 18, 1939 2,347,315 Fill Apr. 25, 1944 2,354,148 Shaw July 18, 1944 2,438,454 Riebe Mar. 23, 1948 

